Some Weather Radar systems, such as the Honeywell RDR-4000, transmit pulse compression waveforms whose received signals are pulse compressed during processing. (Some examples of pulse compression waveforms are linear or non-linear FM chirped pulses, Barker codes, etc.) Processing the received data requires that both the transmitted pulse compression waveforms and the received radar signals pass through a system with flat amplitude and linear phase across the bandwidth of the pulse. Phase and amplitude errors in the front end of the system result in degraded system performance by distorting the transmitted and received signals, thereby increasing the range sidelobes after compression. To achieve the required system performance these errors must be held to a fixed level. However, the error budget required for the analog front end is too stringent to guarantee by design over all operating conditions. Because some of the distortion is created by non-linearities in the risetime of the transmitter, traditional frequency-only equalization techniques are not adequate to correct all the errors in the channel. The errors will be different for different waveforms.
The hardware of the weather radar could be improved to be more robust and thereby reduce distortion to an acceptable level. However, this solution would produce a physically larger weather radar system with significant increases in cost per unit.
Therefore, there exists a need for reducing distortion in a pulse-compression weather radar system without increasing hardware complexity and without significantly increasing cost per unit.